From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EDA13655CA for ; Tue, 21 Jul 2026 14:11:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784643069; cv=none; b=praW68ebb6+3uSiogbhMKR1oZ5nLzzzTKGlg4yGOw8IjutQfzGbKwIUMidPqeaOmYtZioE2xU4pRkgBM6CymHHQqzTAqi8/ymGSPsLhx1npATaJrR/NsDQApkTOSKT9KKq/3AeNmPXeq6sa9Ao+F1+JHUC+7hZ8I2y4cwi8mqOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784643069; c=relaxed/simple; bh=/t4L62O2lkJU6oAtlmXjZps7K7MJG7x/rP5d50KtcAs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iCBJBlzyHw56QDmF8Z2nJlghzAS3WbSfQqJPZfTHG0fJ8sDwtx+6+c6Moa61qACs9WqZQg8+ykTh/YJtxmksHoF1sSN5nqAWOURzAMk1rx9GNSiU5jGBFlGD0qlj1tA/xwkdvjxFIYChqlr7Yz/Cuhyo7N5RBUtbyI+2WNMyJ78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BgI3vLPf; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BgI3vLPf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DA831F000E9; Tue, 21 Jul 2026 14:11:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784643067; bh=XyHikuOC9nWaWKAn+NSw7iThf8fJrsQtOY4LnIXDoEs=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=BgI3vLPfcqLuqUjcFzOrlOgvUJ09LZr9SUDs/PnEhLNJ5Ku1PHSP0gVwLEwYAz0xl Eu7yW81ZOjJ0v03yoN513lVuN9EupR5lZMHoj5IK1n2L2+sR6PcIu2QzOl8z7IifmU UelTrFsP1DoNqV6SHxaCQ+kjeQzB0lLpMm9Pyy5E= Date: Tue, 21 Jul 2026 16:10:58 +0200 From: Greg Kroah-Hartman To: Salvatore Bonaccorso Cc: stable , Sasha Levin , Thomas Gleixner , Wongi Lee , Jungwoo Lee , Oleg Nesterov Subject: Re: RFC: How to backport 920f893f735e ("posix-cpu-timers: Prevent UAF caused by non-leader exec() race") down to 5.15.y? Message-ID: <2026072148-saggy-broken-3ee6@gregkh> References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Jul 13, 2026 at 11:57:27PM +0200, Salvatore Bonaccorso wrote: > Hi, > > 920f893f735e ("posix-cpu-timers: Prevent UAF caused by non-leader > exec() race") talks about a UAF, and the commit was CC'ed for stable. > While checking it I noticed the commit though won't apply cleanly. I > was thinking of needing to pick 6fdb2677a594 ("posix-timers: Expand > timer_[re]arm() callbacks with a boolean return value") beforehand as > preparatory change, and then 920f893f735e ("posix-cpu-timers: Prevent > UAF caused by non-leader exec() race"). Would that be sound/sensible? > > At least that would apply cleanly (though not yet even compile tested) > to 7.1.y and 6.18.y but then already not anymore to 6.12.y, which will > need more adjustments. > > Thomas, would you intend to provide backports from you directly? > > The two patches reflect this RFC. These look sane, I've queued them up now, thanks! greg k-h